Outcomes of adult orthotopic heart transplantation with extended allograft ischemic time.

BACKGROUND: Heart procurement for orthotopic heart transplant (OHT) is limited by the conventional 4 hours of ischemic time (IT). Based on a recent report from our center showing that extended IT from a young donor group is safe, we widened our geographical reach, resulting in almost 40% of our transplants having an IT > 4 hours. METHODS: We retrospectively reviewed records of adult patients who underwent OHT from January 2006 to December 2011. The primary outcome was survival, and secondary outcomes included resource utilization, end-organ dysfunction, and acute cellular rejection. Overall survival was analyzed using Kaplan-Meier curves and log-rank tests. Secondary outcomes were compared with a combination of parametric and nonparametric statistics. RESULTS: A total of 323 patients underwent OHT. There was a significant difference in overall survival between the standard and extended IT groups (85.7% vs 76.4%, P = .03). There were no significant differences between the groups for secondary outcomes except a higher incidence of liver dysfunction in the extended IT group (84.9% vs 73%, P = .01). Further analysis revealed that mortality remains similar if IT is below 4 hours and between 4 and 5 hours, but begins to climb after 5 hours, driving the difference between our standard and extended IT. CONCLUSIONS: Limited donor availability for OHT dictates alternative strategies to enlarge the donor pool. Although there is an overall increasing risk with extended IT beyond 4 hours, it may be possible to safely increase the threshold to at least 5 hours without compromising the outcomes.

Lyt phenotype and H-2 compatibility requirements of effector cells in the delayed-type hypersensitivity response to dengue virus infection.

The nature of effector cells which mediate delayed-type hypersensitivity (DTH) to dengue type 2 virus and the influence of the H-2 complex on the cellular transfer of DTH was investigated. The DTH effector cells appeared to consist of two types of T cells, one Lyt-1.1+, the other Lyt-2.1+ or, alternatively, an interaction between these two T cell subsets may be required for maximal expression of DTH. Cellular transfer of DTH reactivity also required compatibility at the K and D or I region of the H-2 complex. Compatibility at the D region alone was not sufficient for transfer of DTH. The significance and implications of these findings are discussed.

Demonstration of a cytotoxin from Campylobacter jejuni.

A 48-hour culture filtrate of Campylobacter jejuni was found to produce cytopathic effects on three human cell lines--that is, HeLa, MRC-5 and Hep-2. The cytopathic effects observed include cell rounding, loss of adherence and cell death after 24-48 h of incubation. Such morphological changes were observed with eight of the eleven strains of Campylobacter jejuni isolated from the blood/stools of patients who suffered from either acute gastroenteritis or septicaemia. The toxic factor did not retain its activity after treatment at 100 degrees C for 30 min. Trypsinisation of the filtrate totally abolished its toxic activity thus indicating that it was probably protein in nature. It is most probably an extracellular toxin as bacterial sonicates did not produce any toxic effect. This study reports the finding of toxic factor(s) in the culture filtrate of Campylobacter jejuni which is cytotoxic to human tissue culture cells.